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Overview

These properties control shader-specific options. They are in the Material Options folder in the list of properties available under the Render Properties tab of the Edit parameter interface window. Select a node, and in the parameter editor click the Gear menu and choose Edit rendering properties to add or remove properties to a render driver, camera, object, shader, or properties node.

Properties

glTF

glTF AlphaMode

Specifies how the alpha value of the main factor and texture should be interpreted: Opaque, Mask, Blend. These correspond to how the glTF 2.0 spec interprets them.

glTF AlphaCutoff

When glTF AlphaMode is set to Mask, this value specifies the cutoff threshold. If the alpha value is greater than or equal to the cutoff, then it is rendered fully opaque, otherwise, it is rendered as fully transparent. This is ignored for other modes.

IFD Bounds

The Mantra and RenderMan renderers add some properties automatically to procedural geometry shaders.

Bounding Box

How the bounding box for the procedural is specified.

SOP Bounds

Path to a SOP which defines the bounds.

Min Bounds

Minimum bounds.

Max Bounds

Maximum bounds.

OpenGL

These properties control how Houdini displays surfaces in the OpenGL viewport. These properties correspond to variables defined by the OpenGL specification.

Ambient

Ambient material color. This controls how the material reacts to ambient lighting, by multiplying the total ambient light cast on the material. Decreasing this value will make the material less sensitive to ambient lighting.

Ambient Intensity

Adjust the ambient material color intensity. Multiplies Ambient color.

Diffuse

Diffuse material color. This controls how the material reacts to diffuse lighting, by multiplying the total diffuse light cast on the material. Decreasing this value will make the material less sensitive to diffuse lighting.

Enable Diffuse

Toggles contribution of the diffuse color. When off, the material will have no diffuse lighting.

Diffuse Intensity

The diffuse intensity multiplies the Diffuse color, allowing it to be easily adjusted without affecting the its hue or saturation.

Diffuse Roughness

The diffuse roughness determines the falloff of the Oren-Nader shading model used for diffuse lighting.

Specular

Specular material color. This controls how the material reacts to specular highlights, by multiplying specular highlights on the material. Decreasing this value will dim the material’s specular highlights.

Specular Tint

Amount to tint the specular reflection with the Specular material color. This controls how the material reacts to specular highlights, by multiplying specular highlights on the material. Decreasing this value will desaturate the specular highlight to (1,1,1).

Enable Specular

Toggles contribution of the specular color. When off, no specular highlights will appear.

Specular Intensity

The specular intensity multiplies the Specular color, allowing it to be easily adjusted without affecting the its hue or saturation.

Metallic Edge

Metallic edge tint for metallic materials. At grazing angles, metallic objects reflect with the tint rather than their specular tint.

Metallic

Metallic factor, from 0-1. The more metallic a surface is (approaching 1), the less diffuse and more reflection the material will have. A metallic factor closer to zero behaves more like a dielectric material.

Inner IOR

Index of refraction of the material, used for fresnel calculations and reflection.

Specular Model

Specifies the model to use for specular highlights on the material: phong, blinn or ggx. Phong and Blinn are quick approximations, GGX is a more realistic and computationally expensive specular model. This can also be set to lambert to remove specular highlights altogether.

Emission

Emission material color. The emission color is independent of lighting, and will appear as a constant color added to the diffuse, ambient, and specular lighting contributions.

Enable Emission

Toggles contribution of the emission color. When off, the material will not be emissive.

Emission Intensity

The emission intensity multiplies the Emission color, allowing it to be easily adjusted without affecting the its hue or saturation.

Roughness

Specular roughness. Rougher surfaces have larger but dimmer specular highlights. The valid range is 0 to 1.

Shininess

Specular shininess, which is just the inverse of Roughness (1/ogl_rough). If Roughness is also present it takes precedence. This property is for backwards compatibility with shaders that use shininess instead of roughness.

Use Geometry Color

When enabled, the color on the geometry (Cd) is multiplied by the material color. When off, it is ignored.

Use Packed Color

When enabled, the color on the packed primitive (Cd) is multiplied by the material color. When off, it is ignored.

Alpha

Opacity of the surface. Opaque surfaces have an opacity of 1. Decreasing the value will make the material more translucent, and a value of 0 will cause it to disappear entirely.

Alpha Parallel

Opacity of the surface when the surface is parallel to the viewing direction Opaque surfaces have an opacity of 1. Decreasing the value will make the material more translucent, and a value of 0 will cause it to disappear entirely.

Transparency

Defines the transparency of the surface, which overrides the Alpha and Alpha Parallel properties if it is present. A value of zero means the surface has no transparency and is thus completely opaque. A value of one means that it is completely transparent and only reflections based on the Index of Refraction will be seen.

Enable Alpha and Transparency

When disabled, Alpha, Alpha Parallel, and Transparency will have no effect. When enabled, Transparency is respected, and if not present, then Alpha and Alpha Parallel. This has no effect on Shader Alpha.

Shader Alpha

When present and enabled, this forces a transparency pass. This should be used when a custom shader generates alpha information without using the known GL alpha and texture parameters. If disabled or absent, the material is only considered transparent if one of the alpha parameters is less than one, or the diffuse or opacity texture has non-opaque alpha. If no materials are considered transparent, a transparency pass is not performed.

Use Lighting

Whether to use lighting to shade this surface (1), or fill it with a constant color (0).

Use Emission Map

When enabled, use the map specified in ogl_emissionmap for emission. If this property is not present, it is assumed to be enabled.

Emission Map

An image file used for emission texturing. Unlike a diffuse map, the emission map is not affected by lighting and appears constant. The RGB values of the emission map are multiplied by the ogl_emit color which defaults to (0,0,0), so this should be set to (1,1,1) if an emission map is used. The alpha of an emission map is ignored.

Use Diffuse Map Alpha

When enabled, the alpha channel of the base diffuse map is used to determine the surface’s opacity. When disabled, it is ignored.

GLSL Shader

Specifies a custom GLSL shader to use for the viewport. The shader can be given as a program file (.prog, which contains a list of shader files, inputs and outputs) or as a whitespace separated list of shader files. The extensions define the shader stage type:

  • .vert: vertex shader

  • .frag: fragment shader

  • .geom: geometry shader

  • .tcs: tessellation control shader (GL4.0+)

  • .tes: tessellation evaluation shader (GL4.0+)

The format for the program file format is documented in the OpenGL shading section.

Reflect

The reflectiveness of the material, from 0 (not at all reflective) to 1 (completely reflective).

Reflect Map

Texture map which modulates the reflectiveness of the material. This is multiplied by the GL Reflect parameter for the overall reflectivity.

Reflect Multiplies IOR

When enabled, the reflection map value is multiplied by the Index of Refraction before using IOR in lighting computations. The operation is IOR * (1+reflect), so that a value of zero in the map leaves the IOR as is, negative values decrease IOR, and positive values increase IOR.

Reflect Map Channel

The Texture map channel from which reflectivity is selected, either the luminance of the color or one of the red, green, blue, or alpha channels.

Coat Intensity

Intensity of coat specular reflections. If the intensity is zero, the material does not have a coat. Coat reflections are only supported in High Quality Lighting.

Coat Roughness

The roughness of the coat layer, from 0 to 1. Zero is highly reflective while one is diffuse.

Coat Specular Model

Specular model of the coat layer, which can be Phong, Blinn, or GGX.

Use Coat Intensity Map

When enabled, use the map specified in ogl_coat_intensity_map for the coat intensity. If this property is not present, it is assumed to be enabled.

Coat Intensity Map

Texture map to modulate coat intensity. The texture map value is multiplied by the Coat Intensity to produce the final coat intensity value.

Coat Intensity Channel

The channel of Coat Intensity Map from which coat intensity is selected, either the luminance of the color or one of the red, green, blue, or alpha channels.

Use Coat Roughness Map

When enabled, use the map specified in ogl_coat_roughness_map for the coat roughness. If this property is not present, it is assumed to be enabled.

Coat Roughness Map

Texture map to modulate coat roughness. The texture map value is multiplied by the Coat Roughness to produce the final coat roughness value.

Coat Roughness Channel

The channel of Coat Roughness Map from which coat roughness is selected, either the luminance of the color or one of the red, green, blue, or alpha channels.

Texture Layers

Creates multiple layers of diffuse textures.

Use Texture #

Enable diffuse texture for layer #. If this property is not present, the map is assumed to be enabled.

Texture #

Texture map to use for diffuse layer #. UDIM textures can be used by placing %(UDIM)d in the filename where the UDIM number is, and UVTile textures by using %(UVTILE)d or %(U)d and %(V)d.

UVSet #

UV Set to use for diffuse layer #. The naming scheme for the standard uv sets is uv, uv2, uv3. If no uv set is specified, the default uv set for the layer will be used (eg. uv for layer 1, uv2 for layer 2).

Minification Filter

When the texture is applied to geometry such that there are more texels per screen pixels, OpenGL uses a minification filter to reduce aliasing noise. By default, trilinear filtering is used to smooth out the texture, which requires the Use Mip Map display option to be on, otherwise Linear is used.

Magnification Filter

When the texture is applied to geometry such that a single texel is applied to multiple screen pixels, OpenGL uses a magnification filter to reduce pixelation in the texture. By default a bilinear interpolation is used, but no filtering can also be selected as well. Magnification filtering does not use or require mipmapping.

Texture Wrap

Defines how textures are displayed outside of the 0-1 range, using one of three wrapping modes. If Texture V Wrap isn’t specified, this setting is used for both U and V.

Repeat

The texture is repeated in a tiling pattern.

Streak

The texture coordinate is clamped to 0-1, streaking the edge pixels when outside of this range..

Decal

The texture color is (0,0,0,0) outside of 0-1.

Mirror

The texture is repeated in a tiling pattern, flipping the texture each time.

Texture V Wrap

Defines how texutres are sampled when the V coordinate is outside of /props/0,1. If this is not specified, Texture Wrap is used for U and V, otherwise Texture Wrap only applies to U and this parameter controls V.

Normal Map Style

Selects between using a Bump Map or a Normal Map for perturbing geometric normals. The default is to use a normal map.

Use Normal Map

When enabled, use the map specified in ogl_normalmap for the normal map. If this property is not present, it is assumed to be enabled.

Normal Map

Use a normal map to specify normals instead of interpolating normals across a polygon. The RGB values are used for the normal’s XYZ vector.

Normal Map Type

Specifies the space that the normal map operates in: UV Tangent, World, or Object space.

Normal Scale

Scales the X and Y components of a tangent normal map to increase or decrease the effect the normal map has on the normals.

Normal Map Range

The range of the normal map is either 0-1 (8b map) or -1 to 1 (floating point map). This bias must match the type of normal map used.

Flip Normal Map X

Flip the normal’s X direction when applying the normal map. This may be needed for normal maps generated by other applications.

Flip Normal Map Y

Flip the normal’s Y direction when applying the normal map. This may be needed for normal maps generated by other applications.

Normal Layer

The texture layer that the UV coordinates for the normal map are sourced from.

Use Bump Map

When enabled, use the map specified in ogl_bumpmap for the bump map. If this property is not present, it is assumed to be enabled.

Bump Map

Use a bump map to perturb normals to give the illusion of depth to a flat polygon.

Bump Scale

Scales the bumps to increase or decrease the apparent size of the bumps.

Bump Layer

The texture layer that the UV coordinates for the bump map are sourced from.

Invert Bumps

Inverts the bumps so that they appear to be going into the object instead of out.

Use Roughness Map

When enabled, use the map specified in ogl_roughmap for the roughness map. If this property is not present, it is assumed to be enabled.

Roughness Map

Texture map for Roughness. Rougher surfaces have larger but dimmer specular highlights. This overrides the constant ogl_rough.

Invert Roughness Map (Glossiness)

Invert the roughness map so that it is interpreted as a gloss map - zero is no gloss (dull), one is very glossy (shiny).

Roughness Channel

Texture component used for Roughness within the Roughness texture map, which can be the luminance of RGB, red, green, blue or alpha. This allows roughness to be sourced from packed texture maps which contain parameters in the other texture channels.

Use Metallic Map

When enabled, use the map specified in ogl_metallicmap for the metallic map. If this property is not present, it is assumed to be enabled.

Metallic Map

Texture map for Metallic. The GL Metallic parameter is multiplied by the texture map value.

Metallic Channel

Channel of the metallic texture map to sample (luminance, red, green, blue, alpha).

Use Occlusion Map

When enabled, use the map specified in ogl_occlusionmap for the occlusion map. If this property is not present, it is assumed to be enabled.

Occlusion Map

Texture map for Occlusion. The diffuse color is multiplied by the occlusion.

Occlusion Channel

Channel of the occlusion texture map to sample (luminance, red, green, blue, alpha).

Use Specular Map

When enabled, use the map specified in ogl_specmap for the specular map. If this property is not present, it is assumed to be enabled.

Specular Map

The image file to use for modifying specular reflections. The RGB values of the file are multiplied by the specular colors of lights when shading.

Specular Layer

The texture layer that the UV coordinates for the specular map are sourced from.

Use Opacity Map

When enabled, use the map specified in ogl_opacitymap for the opacity map. If this property is not present, it is assumed to be enabled.

Opacity Map

The image file to use for the opacity of the material. Only the alpha channel is used in an RGBA image file. The map values are multiplied by both ogl_alpha or ogl_transparency, and point/vertex alpha, if present.

Invert Opacity Map

Invert the values of the opacity map so that zero is opaque and one is completely transparent. When off, zero is completely transparent and one is opaque.

Opacity Layer

The texture layer that the UV coordinates for the opacity map are sourced from.

Use Environment Map

When enabled, use the map specified in ogl_envmap for the environment map. If this property is not present, it is assumed to be enabled.

Environment Map

The image file that defines an environment map for reflection mapping. If the image file is an RGBA image, it is assumed to be a lat-long map. If a deep raster image with 6 planes is specified, it is assumed to be a cube map if the planes are named Left, Right, Top, Bottom, Front, and Back.

The reflection color is multiplied by the specular map’s RGB, if one is present.

Env Map Rotation

Rotates the environment map using Euler rotation angles.

Env Rotate Order

The rotation order for the Euler rotation angles. Can be one of xyz, xzy, yxz, yzx, zxy, zyx.

Reflection Intensity

Scales the reflection color sourced from the environment map to alter the intensity of reflections.

Use Displacement Map

When enabled, use the map specified in ogl_displacemap for displacement mapping.

Displacement Map

The image file that defines a height-based displacement. The surface will be tessellated and displaced along the normal by the height when this map is valid.

Displace Scale

Factor applied to the height sampled from the displacement map, after ogl_displaceoffset has been added. This affects the scale of the displacement.

Displace Offset

Value added to the height sampled from the displacement map. Usual values are 0 and -0.5, depending on whether the height in the map is centered around 0 or 0.5.

Displace Method

Displacement can be done along the surface normal ("Along Normal") or using full vector displacement ("Vector").

Displace Vector Space

For full vector displacement, the vector can be relative to the UV tangent space, object space, or world space.

Displace Up Vector

Allows the vector to be interpreted as XYZ or XZY. Some applications export vector displacement in XZY order. Houdini uses XYZ by default.

OpenGL Hair

Diffuse Intensity

Controls the intensity of the diffuse component of the hair.

Diffuse Root Color

Diffuse color of the hair at its root (u=0).

Diffuse Tip Color

Diffuse color of the hair at its tip (u=1).

Use Diffuse Map

Enable the use of a texture map lookup for the overall diffuse color of the hair.

Diffuse Map

The texture map for the overall diffuse color of the hair. It is multiplied by the blended diffuse root and tip color. The map lookup is based on the hair’s UV value.

Diffuse Blend Ramp

An op: reference to a ramp parameter which controls the blending between the root and tip diffuse colors.

Specular Intensity

Controls the intensity of the specular component of the hair.

Specular Angle

Produces a specular highlight when the reflected ray is within a certain number of degrees of the eye ray. 0 maps to 0 degrees (no specular produced) and 1 maps to 180 degrees (all angles produce some specular reflection). The specular lobe uses a Gaussian falloff.

Specular Shift

Shifts the specular highlight up or down the hair.

Specular Root Color

Color of the specular highlight of the hair at its root (u=0).

Specular Tip Color

Color of the specular highlight of the hair at its tip (u=1).

Use Specular Map

Enable the use of a texture map lookup for the overall specular color of the hair.

Specular Map

The texture map for the overall specular color of the hair. It is multiplied by the blended specular root and tip colors. The map lookup is based on the hair’s UV value.

Specular Blend Ramp

An op: reference to a ramp parameter which controls the blending between the root and tip specular colors.

Alpha

Makes hair translucent if less than 1.0 (opaque). The viewport uses a sample-masking technique to approximate transparency which is more accurate as the number of samples in the framebuffer increase. The default is 4 samples.

Alpha Blend Ramp

An op: reference to a ramp parameter which controls the falloff of opacity from root (0.0) to tip (1.0).

Randomize Diffuse Hue

When enabled, the hue of the final diffuse hair color is adjusted slightly by a random amount. The hue range is specified by ogl_hair_diff_random_hue_range.

Diffuse Random Hue Range

Controls the amount of random hue variation of the final diffuse hair color when ogl_diff_random_hue is enabled.

Randomize Diffuse Saturation

When enabled, the saturation of the final diffuse hair color is adjusted slightly by a random amount. The saturation range is specified by ogl_hair_diff_random_sat_range.

Diffuse Random Sat Range

Controls the amount of random saturation variation of the final diffuse hair color when ogl_diff_random_sat is enabled.

Randomize Diffuse Intensity

When enabled, the intensity of the final diffuse hair color is adjusted slightly by a random amount. The intensity range is specified by ogl_hair_diff_random_int_range.

Diffuse Random Int Range

Controls the amount of random intensity variation of the final diffuse hair color when ogl_diff_random_int is enabled.

Randomize Specular Intensity

When enabled, the intensity of the final specular hair color is adjusted slightly by a random amount. The intensity range is specified by ogl_hair_spec_random_int_range.

Specular Random Int Range

Controls the amount of random intensity variation of the final specular hair color when ogl_spec_random_int is enabled.

RIB Bounds

Bounding Box

How the bounding box for the procedural is specified.

SOP Bounds

Path to a SOP which defines the bounds.

Min Bounds

Min bounds.

Max Bounds

Max bounds.

Shading

Co-Shader Handle

This property is not documented.

Properties